[Chemical studies of Strobilanthes cusia]

Seven compounds have been isolated from the whole plant of Strobilanthes cusia (Nees) O. Ktze. Three of them are triterpenes (I-III), two are indole alkaloids (IV, V), two are quinazolinone alkaloids (VI, VII). On the basis of spectral analysis and physicochemical properties, their structures were established as lupeol (I), betulin (II), lupenone (III), indigo (IV), indirubin (V), 4(3H)-quinazolinone (VI), 2,4(1H,3H)-quinazolinedione (VII). VI and VII were found from natural plant for the first time. The results of the pharmacological tests demonstrate that compound V has anticancer activity and compound VI has hypotensive action. Compound VII can be quantitatively determined by HPLC, which may serve as a quality control standard for materia medica and its preparations. Compounds VI and VII have been confirmed by means of synthesis.